<!-- index.html -->
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>dataSubmit</title>
    <style>
        body{
            background-color:gray;
        }
        .box {
            width: 200px;
            height: 150px;
            line-height: 150px;
            text-align: center;
            background-color: orange;
            position: absolute;
            top: 50%;
            left: 50%;
            margin-left: -100px;
            margin-top: -75px;
         }
         a{
            font-size:3em;
         }
    </style>
</head>
<body>
<form action="http://httpbin.org/post" method="post">
    <input type="text" name="username">
    <div class="box">
        <input id="submit" type="submit" name="提交">
    </div>
</form>
</body>
</html>